My phone keeps turning off and on i did what it told me but it just keeps on turning on and off but im not going to lie it did fall in water

Had you tried force restarting your iPhone this is common and this maybe able to stop the loop. To do this press the top volume once and the down volume once then hold down the power button until it goes black until you see the Apple logo. If this doesn’t work take the phone out of the case and try putting the phone in rice. The water might have gone through the power button since the iPhone is water resistant and not waterproof. Once you have it in rice for a while do the process all over again if it still continues to loop it might have been water damaged.

It is definitely a hardware issue then. You can however try connecting it to itunes and restore the phone from there. It will download the new software and install it-Normally takes about 30 m if you have a good internet connection. If this doesn't work then take it to the apple store and they will guide you best if it can be repaired or not.

i also agree with Gio about the rice trick! however, it might be too late now, since your phone parts are already damaged.

Did you buy apple care with your iphone? Is it still covered under warranty- accidental one?

I wish you good luck!